An agent-based model of reality in a cadastre

Abstract

This thesis investigates the institutional structure of social reality. In order to make the analysis possible we focus on a specific domain, the domain of land management, in particular the Austrian cadastre. Since the field of cadastre is highly determined by laws we are able to investigate the structure of reality in a cadastre by the analysis of the cadastral law. We investigate social processes and focus on appropriate case studies, which are the transfer of ownership of a parcel between two persons and the conflict regarding land use between two persons and its resolution by the organizations of the state. The thorough analysis of the institutional structures must rely on a sophisticated theoretical foundation and this thesis applies Searle's theory of institutional reality as its major ontological background. Institutional reality can only be comprehensively described by investigating its relationship and interaction to physical reality and Searle's theory gives the appropriate framework for the analysis. Differing from Searle we assume that the institutional structure of society can be described in terms of the individual knowledge and interaction of the actors in the society. The basic approach of this thesis is the construction of a computational model which can be evaluated by simulating social processes in the model. The correctness of the model and thus of the analysis can be shown by assessing the correspondence between the simulation and the real world process. The model of institutional reality in a cadastre must include representations of the individual knowledge, intentions and behavior of the actors involved since they are the central element determining its structure. We represent individuals in the model by agents and use an agent-based approach as the general conceptual framework for the model construction process. We assume that aspects of the real world can be represented on an abstract level in terms of algebra. This thesis applies an algebraic modeling approach for the representation. We algebraically specify the essential properties of reality and construct a computational model, which forms an algebra and includes the desired properties specified. We use the functional programming language Haskell, which supports this algebraic specification style of the model construction process. The result of the model construction process is an agent-based simulation model, which correctly represents the social processes under consideration. The simulation model can be used to develop applications. We apply the model to show how to assess transaction costs within the simulation and provide one foundation for the objective comparison of cadastral systems. This thesis has a theoretical and a practical dimension. One the theoretical side we contribute to the improvement of our understanding about the structure of social reality. On the practical side we show how to construct tools, which can support the development of more efficient cadastral systems.